A Good Night’s Sleep Lets The Brain Clean Out Waste Linked To Alzheimer’s Disease, Other Disorders

Sleeping on their sides can help people get rid of brain's metabolic waste products more effectively, a study found. Photo: Reuters

Sleep is incredibly for the body and new research states the process necessary to clear out waste and other toxins in the brain is most active when we are asleep. Without this waste removal process, toxic proteins build up in the brain which could lead to Alzheimer’s disease.

Sleep is an important process but it is still unclear why every animal performs such an action. As noted by researchers from the University of Rochester Medical Center, URMC, sleep leaves animals vulnerable to predators and while there are some important functions linked to sleep that does not counteract the deadly consequences of sleep. According to the URMC researchers, sleep is associated with memory consolidation and previously discovered the waste removal system of the brain, known as the glymphatic system.

Sleep deprivation can severely impact health including cognitive function, obesity and high blood pressure, reports the Mayo Clinic. Those factors should make anyone take sleep more seriously but the research by Maiken Nedergaard, from the URMC, reveals another useful aspect of sleep.

The brain has a system for the removal of toxic proteins, such as beta-amyloid which can clump together, that are responsible for Alzheimer’s disease, Parkinson’s disease and other neurological disorders. The process involves flushing brain tissue with cerebral spinal fluid with the waste build up being sent to the circulation system, ultimately ending up in the liver.

The researchers believed this waste removal system may be active when we are asleep as previous research has shown the brain is quite active during sleep. Experimenting with mice, Nedergaard and her team discovered the glymphatic system was incredibly active during sleep, ten times more active than when mice were awake. The researchers believe the brain prioritizes different functions based on energy needs. In the case of using sleep to clean up waste, Nedergaard likens it to a house party after all the guests have left. “The brain only has limited energy at its disposal and it appears that it must choice between two different functional states – awake and aware or asleep and cleaning up,” said Nedergaard in a statement.

As mice were asleep, brain cells shrunk by 60 percent, allowing for more efficient removal of waste. Researchers hope understanding the glymphatic system could lead to new treatments for Alzheimer’s and other neurological disorders. Nedergaard’s research was published in the journal Science.